This annual report covers CAIDA's activities in 2011, summarizing
highlights from our research, infrastructure, data-sharing and
outreach activities. Our current research projects span topology,
routing, traffic, economics, future Internet architectures,
and policy. Our infrastructure activities continue to support
measurement-based studies of the Internet's core
infrastructure, with focus on the health and integrity of the global
Internet's topology, routing, addressing, and naming systems.
We are also dedicating resources to support the infrastructure
measurement and data sharing interests and needs of two U.S. federal
agency programs: the National Science Foundation's International
Research Network Connections (IRNC) program, and the Department of
Homeland Security's Protected Repository of Data on Internet
CyberThreats (PREDICT) data-sharing project.

We continue to expand our Internet
active measurement platform Ark in scale and functionality, and
use this platform to collect and share the largest
Internet topology data sets (IPv4 and IPv6) available to
academic researchers, and share many aggregated annotated
derivative data sets publicly. Our topology measurement
platform supports IPv6 -- by the end of 2011, 28 of our
57 Ark hosting sites provided IPv6 connectivity and topology
measurements. We have dramatically improved existing techniques
for IP address alias resolution for large Internet graphs; we submitted
a paper describing and evaluating the performance of our
algorithms in late 2011, hopefully for publication in 2012.
(Preliminary technical report available on the web site now,
see Topology section of the report.)
Using these new techniques, we collected, analyzed, processed and
released two Internet Topology Data Kit (ITDK) Datasets, reflecting
measurements taken in April and October 2011.
Each 2011 ITDK includes two related router-level topologies,
router-to-AS assignments; geographic location of each router; and
DNS lookups of all observed IP addresses. We are still working on
improving and validating our AS relationship inference
algorithm so that we can add additional annotations to future ITDKs.

On the theoretical side of topology research,
we continued investigation of the geometric model we developed last
year to study the structure and function of complex networks. This
model assumes that hyperbolic geometry underlies many complex
networks, which if true provides a natural explanation for the
heterogeneous degree distributions and strong clustering that
characterize so many complex networks, i.e., they are simple
reflections of the negative curvature and metric property of the
underlying hyperbolic geometry. We also showed that not only
popularity but also similarity acts as a strong force in shaping
complex network structure and dynamics. We developed a framework where
new connections, instead of preferring popular nodes, optimize certain
trade-offs between popularity and similarity. The optimization
framework more accurately describes large-scale Internet evolution
(new links) than previous models, e.g., preferential attachment.
The mathematically inclined will appreciate
our related recent investigation of random bipartite networks using a
hidden variable formalism that facilitates study of the structure
and function of complex networks, as well as
inference of individual characteristics, attributes, and annotations of
nodes in real bipartite networks. Particular applications of interest
are network geometry and navigability.

We gained momentum on our economics and policy research
agenda, focused primarily on explanatory and predictive modeling of
the economics of transit and peering interconnections in the Internet.
Two historical developments contribute to a persistent disconnect
between economic models and actual operational practices on the
Internet. First, the Internet became too complex - in traffic
dynamics, topology, and economics - for currently available analytical
tools to allow realistic modeling. Second, the data needed to
parameterize more realistic models is simply not available. The
problem is fundamental, and familiar: simple models are not valid,
and complex models cannot be validated. We are making progress in
both dimensions: creating more powerful, empirically parameterized
computational tools, and enabling broader validation than previously possible.
We also held the second interdisciplinary Workshop on Internet
Economics (WIE) in December, connecting academic researchers,
commercial Internet facilities and service providers, theorists,
policy makers, and pundits of Internet economics to frame
an Internet economics research agenda, and more specifically
to improve the realism, utility, and predictive power of
economic models of Internet topology and dynamics.

In the first months of 2011, Internet communications were
disrupted in several North African countries in response to civilian
protests and threats of civil war. We analyzed episodes of these
disruptions in two countries: Egypt and Libya. Using both control
plane and data plane data sets in combination allowed us to narrow
down which forms of Internet access disruption were implemented in a
given region over time. Among other insights, we detected what we
believe were Libya's attempts to test firewall-based blocking before
they executed more aggressive BGP-based disconnection. Our methodology
could be used, and automated, to detect outages or similar
macroscopically disruptive events in other geographic or topological
regions.

We are applying our theoretical, empirical, and practical
understandings of the Internet's evolution to engage in the NSF's
exciting Future Internet Architecture (FIA) Research program.
We are participating in the Named Data Networking project, a 12-university
collaboration funded by FIA to explore a generalization of
the Internet architecture that allows naming more than just
communication endpoints, i.e, the source and destination IP address,
but also data (content) itself. This approach shifts the focus from
where -- addresses and hosts in today's Internet -- to what -- the
content that users and applications care about. By naming data instead
of locations, the new architecture transforms data into a first-class
entity while addressing the known technical challenges of the today
Internet: routing scalability, network security, content protection
and privacy. In 2011 we investigated combinations of name-space
structure and network topology that optimize the efficiency of NDN
algorithms and participated in NDN testbed development and evaluation.

Finally, as always, we engaged in a variety of tool development, data-sharing,
and outreach activities, including web sites, peer-reviewed papers,
technical reports, presentations, blogging, animations, and
(six) workshops.
Details of our activities are below. CAIDA's program plan for
2010-2013 is available at
http://www.caida.org/home/about/progplan/progplan2010/. Please do
not hesitate to send comments or questions to info at caida dot
org.

We continued to collect automated DNS reverse lookups for IP addresses
discovered by the Ark probes and annotated the IPv4 topology data with
corresponding DNS names.

Analysis of Observable Topology:

We run the alias resolution tools on the Ark platform and combine the outcomes
to map IP addresses to routers as accurately and completely as feasible.
Using publicly available data from many networks and ground truth data provided
to us by a large ISP, we tested the efficiency and veracity of various
combinations of alias resolution methods. We released a technical report
Internet-Scale IPv4 Alias Resolution with MIDAR: System Architecture detailing the MIDAR system
architecture and submitted a version of this paper to IEEE/ACM Transactions on
Networking for publication in 2012.

Resulting from our improved measurement and analysis
techniques, we collected, analyzed, processed and released two
Internet Topology Data Kit (ITDK) Datasets, using
traceroute data collected as part of the IPv4 Routed /24
Topology Dataset and alias resolution measurements conducted in April
and October 2011. Each 2011 ITDK includes: two related
router-level topologies; router-to-AS assignments;
geographic location of each router; and DNS lookups of all
observed IP addresses.

In January 2011 we temporarily halted the bi-weekly production of
AS-level topologies annotated with business relationships between ASes dataset and started revisions and improvements of our
published algorithms inferring these relationships. We plan to resume
the production of this popular data after completing the changes and
verification of the new algorithms.

Data collected using traceroute-based algorithms underpins research
into the Internet's router-level topology, though it is possible
to infer false links from this data. In Measured Impact of Crooked Traceroute, we examined the inaccuracies
induced from such false inferences, both on macroscopic and ISP
topology mapping. We observed that most per-flow load-balancing
did not induce false links when macroscopic topology is inferred
using classic traceroute. The effect of false links on ISP topology
mapping is possibly much worse, because the degrees of a tier-1
ISP's routers derived from classic traceroute were inflated by a
median factor of 2.9 as compared to those inferred with Paris traceroute.

We continued our work measuring the evolution and dynamics of peering
relationships. In Twelve Years in the Evolution of the Internet Ecosystem, we
analyzed data and studied trends in the evolution of the Internet AS
topology in the last 12 years. This work focused mainly on transit
(customer-provider) links in the AS topology, as these are visible
in data available from public repositories of BGP data.

We published the technical report, "Geocompare: a comparison of public and commercial geolocation databases"
in May 2011. The report attempts a systematic quantitative comparison
of currently available geolocation service providers. The report
describes our process for selecting distance thresholds for comparison,
and our centroid-based algorithm for comparing database lat-long
results against a majority of responses from the set of databases
we evaluated. We presented the work at Network Mapping and Measurement
Conference (NMMC) in May 2011.

Topology Modeling:

We proved that graphs in a general class of self-similar networks have zero
percolation threshold. The considered self-similar networks included random
scale-free graphs with given expected node degrees and zero clustering,
scale-free graphs with finite clustering and metric structure, growing
scale-free networks, and many real networks. The proof and the derivation of
the giant component size in
Percolation in Self-Similar Networks did not require the assumption
that networks were
treelike. Our results rely only on the observation that self-similar networks
possess a hierarchy of nested subgraphs whose average degree grows with their
depth in the hierarchy. We conjecture that this property is pivotal for
percolation in networks.

Analysis of IPv4 and IPv6 address space allocation

In "Tracking IPv6 Evolution: Data We Have and Data We Need", published
in ACM SIGCOMM Computer Communication Review (CCR), vol. 43, no.
3, pp. 43--48, Jul 2011, we evaluate the types of measurement, data,
and analysis needed to inform technical, business, and policy
decisions. We survey available data that have allowed limited
tracking of IPv6 deployment thus far, describe additional types of
data that would support better tracking, and offer a perspective
on the challenging future of IPv6 evolution.

The primary objective of CAIDA's research in Internet routing remains
the development and evaluation of solutions to the impending routing
scalability problems. Our relevant activities focused on two related
sub-topics: greedy routing based on hidden metric spaces underlying
real networks; and the relationship between routing efficiency and
the structure of the network topology. While motivated by Internet
routing, we spent the past year investigating the implications of
this work to other disciplines, physics, biology, chemistry, and
economics.

Activities

We showed that not only popularity but also similarity acts as a strong force
in shaping complex network structure and dynamics. In
Popularity versus Similarity in Growing Networks,
we developed a framework where new connections, instead of
preferring popular nodes, optimize certain trade-offs between
popularity and similarity. The framework admits a geometric
interpretation, in which preferential attachment emerges from local
optimization processes. As opposed to preferential attachment, the
optimization framework accurately describes large-scale Internet
evolution, predicting new links in the Internet with remarkable
precision. The developed framework can thus potentially be used
to predict new links in evolving networks, and provides a
different perspective on preferential attachment as an emergent phenomenon.

We introduced and studied random bipartite networks with hidden variables.
The hidden variable formalism developed in
Hidden variables in bipartite networks has been a powerful tool in studying
the structure and function of complex networks, and can also be
useful in inferring individual characteristics, attributes, and
annotations of nodes in real bipartite networks. Particular
applications of interest are network geometry and navigability.

The high-level objective of this research is to create a scientific
basis for modeling Internet interdomain interconnection and dynamics.
We aim to understand the structure and dynamics of the
Internet ecosystem from an economic perspective, capturing relevant
interactions between network business relations, internetwork
topology, routing policies, and resulting interdomain traffic flow.

Activities

We developed GENESIS, a computational model of interdomain network
formation that captures strategy selection dynamics by autonomous
networks. This model provides the underpinnings for our study
of peering strategy selection by autonomous networks in the Internet.
We submitted a paper for publication in IEEE Infocom 2012.

We regularly responded to requests from government agencies and policymaking
bodies for comments and positions that inform policy with the best available
empirical data. kc claffy served on two ICANN advisory committees, RSSAC and
SSAC, and continued on in her second year as a member of the FCC Technical
Advisory Committee (TAC). She wrote blog commentaries about TAC meetings in
March and in June, 2011.

We seek to develop new methods of analysis and aggregation of Internet
measurement data from multiple available sources in order
to shed light on various Internet security related events, including
global connectivity disruptions due to political or catastrophic causes.
Our methodology and findings can form the basis for
automated early-warning detection systems for large-scale Internet
outages.

Activities

In the first months of 2011, Internet communications were disrupted
in several North African countries in response to civilian protests
and threats of civil war. In "Analysis of Country-wide Internet Outages Caused by Censorship",
we analyzed episodes of these disruptions in two countries: Egypt and
Libya. Using both control plane and data plane data sets in combination
allowed us to narrow down which forms of Internet access disruption
were implemented in a given region over time. Among other insights,
we detected what we believe were Libya's attempts to test firewall-based
blocking before they executed more aggressive BGP-based disconnection.
Our methodology could be automated and used to detect outages or
similar macroscopically disruptive events in other geographic or
topological regions.

The main goal of this collaborative project is research, development, and
testbed deployment of a new Internet architecture that replaces IP with a
network layer routing directly on content names.

Activities

The list of collaborating institutions includes UC Los Angeles, Palo Alto
Research Center (PARC), Colorado State University, University of Arizona,
University of Illinois/Urbana-Champaign, UC Irvine, UC San Diego, University of
Memphis, Washington University, and Yale University, and is led by Lixia Zhang
(UCLA) and Van Jacobson (PARC). CAIDA researchers participated in activities of
the Evaluation and Measurement, Theory, and Routing/Forwarding teams.

We deployed and maintained a local node on the national NDN testbed
using the CCNX hub
software.

To test the applicability of the hyperbolic greedy routing methods to NDN, we
conducted simulations forwarding packets on the new CCNx network. We extracted the
Autonomous System (AS) graph of the testbed and mapped each AS number to its
hyperbolic coordinates using the supplementary data from our 2010 paper
Sustaining the Internet with Hyperbolic Mapping. We then evaluated
the performance of modified greedy forwarding strategies using the metrics of
the delivery success ratio and three types of stretch.

In May, CAIDA researchers participated in the first NDN retreat at PARC,
Palo Alto, CA.

CAIDA researchers participated in the Future Internet Architecture Program
Meeting and contributed to discussions of the four projects funded by FIA
and the security features inherent to each architecture design.

Archipelago (Ark) is CAIDA's active measurement infrastructure. It aims
to enable large-scale Internet measurements, while reducing the effort needed
to develop, deploy and conduct sophisticated experiments.
Ark represents a step toward a community-oriented measurement infrastructure
as it allows CAIDA collaborators to run their vetted measurement tasks on a
security-hardened distributed platform.

Activities

By the end of 2011, we increased the number of vantage points to 57
Ark monitors deployed in 29 countries.

We continued to improve our measurement techniques and analysis
methodologies for alias resolution inferences. In 2011, we released
the following tools to the public:
kapar,
MIDAR,
Motu,
mper, and
rb-mperio.

We added more monitors with native IPv6 connectivity to the Ark
infrastructure. As of the end of 2011, Ark had 28 monitors collecting the
data on the emerging IPv6 global topology.

We continued support for spoofer experiment
(collaboration with R. Beverly, NPS).

Outreach

In 2011, CAIDA researchers published 9 papers and non-CAIDA researchers
published 11 papers that used Ark data.

We develop and maintain a passive data collection system known as the
Network Telescope, in order to study security related events by monitoring
and analyzing unsolicited traffic arriving to a globally routed
underutilized /8 network.

Activities

Since data storage is becoming considerably more expensive, we
prioritized telescope data curation and meta-data preservation.

We started improving our software infrastructure
for processing, management, analysis, visualization and reporting
on data collected with the UCSD Network Telescope.

We developed iatmon (Inter-Arrival Time Monitor), a freely available
measurement and analysis tool that allows one to separate one-way traffic
into clearly defined subsets: 14 source types and 10 inter-arrival-time
based groups. We used this tool to observe changes in one-way traffic at
the UCSD Network Telescope over the first half of 2011. A paper
One-way Traffic Monitoring with iatmon was submitted to PAM.

The goal of the Department of Homeland Security project Protected Repository
for the Defense of Infrastructure Against Cyber Threats (PREDICT) is to
provide vetted researchers with current network operational data in a secure
and controlled manner that respects the security, privacy, legal, and economic
concerns of Internet users and network operators. CAIDA supports PREDICT goals
as Data Provider and Data Host and also plays an advisory role in developing
technical, legal, and practical aspects of PREDICT policies and procedures.

Goals

Activities

We received six user requests via the PREDICT portal during 2011 all of whom received access to our data.

We continued drafting a proposed framework document in the spirit of the
Belmont Report that would address ethical principles and guidelines
for the protection of human subjects in Information and Communications
Technologies research.

Originally funded by the NSF award (OCI-0137121) "Correlating
Heterogeneous Measurement Data to Achieve System-Level Analysis of
Internet Traffic Trends", CAIDA built the Internet Measurement Data
Catalog (IMDC) to facilitate searching for and sharing of data and
metadata among researchers. Since its launch in June 2006 at www.datcat.org the catalog
has received contributions of metadata indexing nearly 19TB of data.
Lack of funding and increased Oracle database licensing cost required
that we disable the IMDC temporarily while we integrate lessons
learned into our transition from this research prototype to the
proposed increased operational capabilities.

Based on the lessons we learned during the development and operation
of IMDC, we began to upgrade and modify the underlying DatCat
service with three tasks: streamline the user experience by simplifying
the metadata entry process; migrate from a proprietary database
backend (Oracle) to a completely open source solution; and expand
the community of the catalog users to a broader range of cybersecurity
and other researchers. We completed the third task this year and
plan to complete the first two tasks in 2012.

Activities

We designed and developed a public forums interface integrated
with the IMDC to hold discussion of data sharing issues and to
answer frequently asked questions regarding the IMDC and the
information it contains.

NSF International Research Network Connections Program (IRNC) has
funded five projects to provide network connections linking U.S.
research networks with peer networks in other parts of the world.
The goal of our IRNC Special Project is to support the IRNC community
measurement efforts by fostering and leading discussion of how to best make
IRNC data and statistics available, and by adapting CAIDA measurement
technologies for IRNC community needs.

Activities

We added Internet Protocol Version 6 (IPv6) capabilities to the Coralreef
suite of network data collection and analysis tools for processing network
traces and flows. We also added support for prefix preserving IPv6 address
anonymization, an option to apply IPv4 anonymization policy to IPv4
addresses embedded within IPv6 addresses (IPv4-mapped, SIIT, Teredo,
6to4, 6over4, ISATAP), an option to anonymize IP addresses in nested
headers (e.g. IPIP, or the original IP header in an ICMP error
message) as well as an option to leave multicast addresses intact.
Our next step will be to extend the Coralreef Report Generator software to
better visualize the IPv6 traffic separately from the IPv4 packets.

CAIDA held several conference calls with IRNC ProNET PI Julio Ibarra
and his staff to discuss how he might instrument a hybrid network
router that transits both OpenFlow as well as IP traffic. We discussed
use of CAIDA's Coralreef suite of data collection, analysis, and
reporting tools for reporting and visualization of the IP portion
of the traffic.

We made progress on extending our Archipelago measurement infrastructure
to monitor IRNC sites.

With an introduction by IRNC ProNet PI Julio Ibarra, we obtained contacts
at the Academic Network for State of Sao Paulo (ANSP) and signed and Ark
Memorandum of Cooperation (MoC) with them.

With an introduction by IRNC ProNet PI David Lassner, we worked with
Australia's Academic and Research Network (AARNet).
AARNet accepted our MoC and donated hardware for a new Ark server in Perth, Australia.

ProNet PI Steve Huter provided contacts with two network engineers in
Gambia, where we will deploy an Ark monitor.

IRNC Network Engineer John Hicks provided contacts with the University of
Peradeniya in Sri Lanka where we are pursuing the deployment of
another Ark monitor.

We developed an IRNC Wiki page with the intention for it to serve as a
collection point for IRNC related activities.

In October, we participated in the IRNC PI IRNC PI Meeting and in a concurrent
NSF panel (Washington DC) that focused on how IRNC SP projects
might leverage each other and how the IRNC program might contribute
[data] to the research community.

CAIDA's mission includes providing access to tools for Internet data collection, analysis and visualization to facilitate network measurement and management. However, CAIDA does not receive specific funding for support and maintenance of the tools we develop. Please check our home page for a complete listing and taxonomy of CAIDA tools.

2011 Tool Development

MIDAR

MIDAR stands for Monotonic ID-Based Alias Resolution, is a tool developed by CAIDA that builds on recent work in alias resolution using IP-ID time stamps to scale related techniques to the size of large-scale Internet topologies (millions of nodes) with greater precision and sensitivity. MIDAR, our Monotonic ID-Based Alias Resolution tool, provides an extremely precise ID comparison test based on monotonicity rather than proximity. MIDAR integrates multiple probing methods, multiple vantage points, and a novel sliding-window probe scheduling algorithm to increase scalability to millions of IP addresses. Experiments show that MIDAR's approach is effective at minimizing the false positive rate sufficiently to achieve a high positive predictive value at Internet scale.

kapar

The "kapar" tool is inspired by the promising foundation presented in Mehmet Gunes' APAR, CAIDA wrote a highly optimized implementation for production use on large-scale Internet topologies, as well as fixing a few bugs and experimenting with our own improvements to the algorithm.

mper

mper is a probing engine that clients can use to conduct network measurements using ICMP, UDP, and TCP probes.

rb-mperio

rb-mperio is a RubyGem for writing network measurement scripts in Ruby that use the mper probing engine. rb-mperio v0.3.0 was released on September 30, 2011.

Motu

Motu is a simple tool for dealiasing pairs of IPv4 addresses. Version 1.0.1 was released on October 5, 2011.

CAIDA Tools Download Report

The table below displays all
CAIDA developed and currently supported tools
distributed via our home page at http://www.caida.org/tools/ and the number of
downloads of each version during 2011.

A Perl module that provides a programmatic interface to several popular graphing packages. Note: Chart::Graph is also available on CPAN.org. The numbers here reflect only downloads directly from caida.org, as download statistics from CPAN are not available.

During the Day In The Life of the Internet (DITL 2011 on April 13-15)) we
collected one-hour passive traces on high-speed internet backbone links
(distributed as part of the CAIDA Anonymized High-speed Internet Traces 2011,
and retained the "live" data collected on the UCSD Network Telescope as well.

1The total size represents actual disk space. If data are stored in
compressed form, the uncompressed size is given in brackets.2The size of this data set varies over time as we store and serve a
rotating window of the last 30 days only. The specified numbers are totals
captured over the whole year.3This includes traces on April 13 during DITL 2011, and traces on
8 June 2011 (IPv6 Day)4This includes 279 GB of data collected during DITL 2011 and 95 GB
on IPv6 Day.

Datasets Distributed in 2011

CAIDA makes some datasets publicly available without restrictions to the
user, while access to other datasets is restricted to academic researchers,
CAIDA members, and government contractors with data access subject to certain
safeguards designed to protect the privacy of monitored communications, to
ensure security of network infrastructure, and to comply with the terms of
our agreements with data providers.

Publicly Available Data

These datasets require that users agree to an Acceptable Use Policy, but are otherwise freely available.

We count the volume of data downloaded per unique user per unique file,
so if a user downloads a file multiple times, we only count that file once for that user.
This significantly underestimates the total volume of data served through our dataservers.

* AS Taxonomy dataset is included in a
mirror of the GA Tech main AS Taxonomy site, and thus does not
represent all access to this data.

Restricted Access Data

These datasets require that users:

be academic or government researchers, or join CAIDA;

request an account and provide a brief description of their
intended use of the data; and

* We count the volume of data downloaded per unique user per unique file,
so even if a user downloads a file 100 times, we only count that file
once for that user. This methodology results in significantly under-counting
the total volume of data served through our dataservers.

Restricted Access Data Requests

The following table shows some statistics about data requests for CAIDA datasets:
the number of requests received, the number of users whose request was granted, and
the number of users that actually downloaded data.

We received about 33 more requests in 2011 then in 2010,
and approved 46 more requests for access to restricted datasets.
About 77.1 % of the users that are granted access actually accessed our
webservers to download data.

As part of our mission to investigate both practical and
theoretical aspects of the Internet, CAIDA staff actively attend,
contribute to, and host workshops relevant to research and better
understanding of Internet infrastructure, trends, topology,
routing, and security. Our web site has a complete listing of past and
upcoming CAIDA Workshops.

From January 11-13, 2011, the University of Cyprus (UCY) hosted an interdisciplinary "Network Geometry" workshop jointly organized by CAIDA, UCSD and UCY. The agenda included short presentations by participants as well as extensive time for discussions and interactions.

On February 9-11, 2011, CAIDA hosted the 3rd workshop on Active Internet Measurements supporting science and policy. This workshop continues the series of Internet Statistics and Metrics Analysis (ISMA) workshops that are held to discuss the current and future state of Internet measurement and analysis.

As part of our efforts on the Internet Laboratory for Empirical Network Science (iLENS) Project, CAIDA hosted a workshop on August 22nd, 2011 to discuss scalable measurement and analysis of BGP and traceroute data.

On December 1-2, 2011, CAIDA and Georgia Tech hosted its second Workshop on Internet Economics. The workshop included presentations by participants, and in depth discussions on how to improve the realism and utility of Internet interdomain connectivity models for trend analysis, as well as predictions of how the Internet ecosystem will look 5-15 years from now. A two-day event to bring
together researchers, commercial Internet facilities and service providers,
technologists, theorists, policy makers, RIR stakeholders, and
pundits of Internet economics to try to frame a concrete and useful
research agenda for the emerging but stunted field of Internet
infrastructure economics. The event
brought together a mix of academia and industry to discuss the topics
surrounding the field of Internet infrastructure economics and AS peering
policies and practices.

On December 5th, 2011, the 4th CAIDA-WIDE-CASFI Joint Measurement Workshop was held in Tokyo, Japan.
This workshop continues a tradition of workshops supporting a three-way collaboration between researchers from CAIDA (USA), WIDE (Japan) and CASFI (South Korea). The Workshop covered miscellaneous research and technical topics of mutual interest for CAIDA, WIDE and CASFI participants and brought various groups together to share their latest research.

Starting in October 2010, CAIDA began hosting the UCSD Complex Network Seminar: Different Angles on Network Complexity, Engineering, and Science (DANCES). As a series of seminars, the goal of DANCES was to bring together junior and senior researchers, including UCSD graduate students and post-docs, studying networks. The seminar fostered communication and collaboration among researchers from diverse disciplines that study networks from different perspectives (physics, biology, sociology, computer science, ECE, math, bioengineering, cognitive science, etc), and provided young researchers a forum to practice their presentation and communication skills. The seminars continued in 2011 to bring in attendees from a diversity of disciplines.

In 2011, CAIDA's web site continued to attract considerable attention from a broad, international audience. The wave of heavy traffic that occurred mid-year is attributed to increased downloads of the recently updated AS Core IPv4 and IPv6 graph, which was publicized at the various conferences and workshops that CAIDA staff attended.

The graph and table below present the monthly history of traffic to www.caida.org for 2011. To show a more accurate representation of website traffic, these statistics do not include non-viewed traffic including traffic from spiders, crawlers or other robots.

CAIDA would like to acknowledge the many people who put forth
great effort towards making CAIDA a success in 2011. The image
below shows the functional organization of CAIDA. Please check the
home page for more complete information about CAIDA staff.